﻿using System;    
using System.Text;    
using System.Collections;    
using System.Collections.Specialized;    
using System.Data;    
using System.Data.OleDb;    
using System.Configuration;
using IESN.Tools;
using System.Collections.Generic;   
   
namespace  IESN.DAL   
{    /// <summary>    
    /// 数据访问抽象基础类(ACCESS)    
    /// Copyright (C) 2006-2007 hovertree.net 
    /// All rights reserved    
    /// </summary>    
    public abstract class AccessDBHelper    
    {    
        //数据库连接字符串(web.config来配置)    
        //public static string connectionString = ConfigurationManager.AppSettings["ConnectionString"];    
        // public static string connectionString = System.Web.HttpContext.Current.Server.MapPath(ConfigurationManager.AppSettings["AccessConnectionString"]);    
        //public static string connectionString = ConfigurationManager.AppSettings["AccessConnectionString"];  
        public static string connectionString = ConfigHelper.GetConnectionStringsConfig("DataConStrAccess");
        public AccessDBHelper()    
        {    
        }  
  
        #region 公用方法
  
        public static int GetMaxID(string FieldName, string TableName)    
        {    
            string strsql = "select max(" + FieldName + ")+1 from " + TableName;    
            object obj = AccessDBHelper.GetSingle(strsql);    
            if (obj == null)    
            {    
                return 1;    
            }    
            else  
            {    
                return int.Parse(obj.ToString());    
            }    
        }    
        public static bool Exists(string strSql)    
        {    
            object obj = AccessDBHelper.GetSingle(strSql);    
            int cmdresult;    
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))    
            {    
                cmdresult = 0;    
            }    
            else  
            {    
                cmdresult = int.Parse(obj.ToString());    
            }    
            if (cmdresult == 0)    
            {    
                return false;    
            }    
            else  
            {    
                return true;    
            }    
        }    
        public static bool Exists(string strSql, params OleDbParameter[] cmdParms)    
        {    
            object obj = AccessDBHelper.GetSingle(strSql, cmdParms);    
            int cmdresult;    
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))    
            {    
                cmdresult = 0;    
            }    
            else  
            {    
                cmdresult = int.Parse(obj.ToString());    
            }    
            if (cmdresult == 0)    
            {    
                return false;    
            }    
            else  
            {    
                return true;    
            }    
        }  
        #endregion  
  
        #region  执行简单SQL语句    
  
        /// <summary>    
        /// 执行SQL语句，返回影响的记录数    
        /// </summary>    
        /// <param name="SQLString">SQL语句</param>    
        /// <returns>影响的记录数</returns>    
        public static int ExecuteSql(string SQLString)    
        {    
            using (OleDbConnection connection = new OleDbConnection(connectionString))    
            {
                using (OleDbCommand cmd = new OleDbCommand(SQLString, connection))    
                {    
                    try  
                    {    
                        connection.Open();    
                        int rows = cmd.ExecuteNonQuery();   
                        
                        return rows;    
                    }    
                    catch (System.Data.OleDb.OleDbException E)    
                    {    
                        connection.Close();    
                        throw new Exception(E.Message);    
                    }    
                }    
            }    
        }    
  
        /// <summary>    
        /// 执行SQL语句，设置命令的执行等待时间    
        /// </summary>    
        /// <param name="SQLString"></param>    
        /// <param name="Times"></param>    
        /// <returns></returns>    
        public static int ExecuteSqlByTime(string SQLString, int Times)    
        {    
            using (OleDbConnection connection = new OleDbConnection(connectionString))    
            {    
                using (OleDbCommand cmd = new OleDbCommand(SQLString, connection))    
                {    
                    try  
                    {    
                        connection.Open();    
                        cmd.CommandTimeout = Times;    
                        int rows = cmd.ExecuteNonQuery();    
                        return rows;    
                    }    
                    catch (System.Data.OleDb.OleDbException E)    
                    {    
                        connection.Close();    
                        throw new Exception(E.Message);    
                    }    
                }    
            }    
        }    
  
        /// <summary>    
        /// 执行多条SQL语句，实现数据库事务。    
        /// </summary>    
        /// <param name="SQLStringList">多条SQL语句</param>        
        public static void ExecuteSqlTran(ArrayList SQLStringList)    
        {    
            using (OleDbConnection conn = new OleDbConnection(connectionString))    
            {    
                conn.Open();    
                OleDbCommand cmd = new OleDbCommand();    
                cmd.Connection = conn;    
                OleDbTransaction tx = conn.BeginTransaction();    
                cmd.Transaction = tx;    
                try  
                {    
                    for (int n = 0; n < SQLStringList.Count; n++)    
                    {    
                        string strsql = SQLStringList[n].ToString();    
                        if (strsql.Trim().Length > 1)    
                        {    
                            cmd.CommandText = strsql;    
                            cmd.ExecuteNonQuery();    
                        }    
                    }    
                    tx.Commit();    
                }    
                catch (System.Data.OleDb.OleDbException E)    
                {    
                    tx.Rollback();    
                    throw new Exception(E.Message);    
                }    
            }    
        }    
  
        /// <summary>    
        /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)    
        /// </summary>    
        /// <param name="strSQL">SQL语句</param>    
        /// <param name="fs">图像字节,数据库的字段类型为image的情况</param>    
        /// <returns>影响的记录数</returns>    
        public static int ExecuteSqlInsertImg(string strSQL, byte[] fs)    
        {    
            using (OleDbConnection connection = new OleDbConnection(connectionString))    
            {    
                OleDbCommand cmd = new OleDbCommand(strSQL, connection);    
                System.Data.OleDb.OleDbParameter myParameter = new System.Data.OleDb.OleDbParameter("@fs", SqlDbType.Image);    
                myParameter.Value = fs;    
                cmd.Parameters.Add(myParameter);    
                try  
                {    
                    connection.Open();    
                    int rows = cmd.ExecuteNonQuery();    
                    return rows;    
                }    
                catch (System.Data.OleDb.OleDbException E)    
                {    
                    throw new Exception(E.Message);    
                }    
                finally  
                {    
                    cmd.Dispose();    
                    connection.Close();    
                }    
            }    
        }

        /// <summary>
        /// 根据表名，获取该表的数据集
        /// </summary>
        /// <param name="tbName">表名称</param>
        /// <returns>数据集</returns>
        public static DataSet GetDataSetByTableName(string tbName)
        {
            string strSql = "SELECT * FROM " + tbName;
            return Query(strSql,tbName);   
        }

        /// <summary>    
        /// 执行一条计算查询结果语句，返回查询结果（object）    
        /// </summary>    
        /// <param name="SQLString">计算查询结果语句</param>    
        /// <returns>查询结果（object）</returns>    
        public static object GetSingle(string SQLString)    
        {    
            using (OleDbConnection connection = new OleDbConnection(connectionString))    
            {    
                using (OleDbCommand cmd = new OleDbCommand(SQLString, connection))    
                {    
                    try  
                    {    
                        connection.Open();    
                        object obj = cmd.ExecuteScalar();    
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))    
                        {    
                            return null;    
                        }    
                        else  
                        {    
                            return obj;    
                        }    
                    }    
                    catch (System.Data.OleDb.OleDbException e)    
                    {    
                        connection.Close();    
                        throw new Exception(e.Message);    
                    }    
                }    
            }    
        }      
  
        /// <summary>    
        /// 执行查询语句，返回SqlDataReader(使用该方法切记要手工关闭SqlDataReader和连接)    
        /// </summary>    
        /// <param name="strSQL">查询语句</param>    
        /// <returns>SqlDataReader</returns>    
        public static OleDbDataReader ExecuteReader(string strSQL)    
        {    
            OleDbConnection connection = new OleDbConnection(connectionString);    
            OleDbCommand cmd = new OleDbCommand(strSQL, connection);    
            try  
            {    
                connection.Open();    
                OleDbDataReader myReader = cmd.ExecuteReader();    
                return myReader;    
            }    
            catch (System.Data.OleDb.OleDbException e)    
            {    
                throw new Exception(e.Message);    
            }    
            //finally //不能在此关闭，否则，返回的对象将无法使用    
            //{    
            //  cmd.Dispose();    
            //  connection.Close();    
            //}      
        } 
   
        /// <summary>    
        /// 执行查询语句，返回DataSet    
        /// </summary>    
        /// <param name="SQLString">查询语句</param>    
        /// <returns>DataSet</returns>    
        public static DataSet Query(string SQLString,string tableName="ds")    
        {    
            using (OleDbConnection connection = new OleDbConnection(connectionString))    
            {    
                DataSet ds = new DataSet();    
                try  
                {    
                    connection.Open();    
                    OleDbDataAdapter command = new OleDbDataAdapter(SQLString, connection);
                    command.Fill(ds, tableName);    
                }    
                catch (System.Data.OleDb.OleDbException ex)    
                {    
                    throw new Exception(ex.Message);    
                }    
                return ds;    
            }    
        }

        ///// <summary>    
        ///// 执行查询语句，返回DataSet    
        ///// </summary>    
        ///// <param name="SQLString">查询语句</param>    
        ///// <returns>DataSet</returns>    
        //public static DataSet Query(List<string> SQLString, string tableName = "ds")
        //{
        //    using (OleDbConnection connection = new OleDbConnection(connectionString))
        //    {
        //        DataSet ds = new DataSet();
        //        try
        //        {
        //            connection.Open();
        //            OleDbDataAdapter command = new OleDbDataAdapter(SQLString, connection);
        //            command.Fill(ds, tableName);
        //        }
        //        catch (System.Data.OleDb.OleDbException ex)
        //        {
        //            throw new Exception(ex.Message);
        //        }
        //        return ds;
        //    }
        //}    

        /// <summary>    
        /// 执行查询语句，返回DataSet,设置命令的执行等待时间    
        /// </summary>    
        /// <param name="SQLString"></param>    
        /// <param name="Times"></param>    
        /// <returns></returns>    
        public static DataSet Query(string SQLString, int Times)    
        {    
            using (OleDbConnection connection = new OleDbConnection(connectionString))    
            {    
                DataSet ds = new DataSet(); 
                try  
                {    
                    connection.Open();    
                    OleDbDataAdapter command = new OleDbDataAdapter(SQLString, connection);    
                    command.SelectCommand.CommandTimeout = Times;    
                    command.Fill(ds, "ds");    
                }    
                catch (System.Data.OleDb.OleDbException ex)    
                {    
                    throw new Exception(ex.Message);    
                }    
                return ds;    
            }    
        }  
  
        #endregion  
  
        #region 执行带参数的SQL语句
  
        /// <summary>    
        /// 执行SQL语句，返回影响的记录数    
        /// </summary>    
        /// <param name="SQLString">SQL语句</param>    
        /// <returns>影响的记录数</returns>    
        public static int ExecuteSql(string SQLString, params OleDbParameter[] cmdParms)    
        {    
            using (OleDbConnection connection = new OleDbConnection(connectionString))    
            {    
                using (OleDbCommand cmd = new OleDbCommand())    
                {    
                    try  
                    {    
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);    
                        int rows = cmd.ExecuteNonQuery();    
                        cmd.Parameters.Clear();    
                        return rows;    
                    }    
                    catch (System.Data.OleDb.OleDbException E)    
                    {    
                        throw new Exception(E.Message);    
                    }    
                }    
            }    
        }      
  
        /// <summary>    
        /// 执行多条SQL语句，实现数据库事务。    
        /// </summary>    
        /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的OleDbParameter[]）</param>    
        public static void ExecuteSqlTran(Hashtable SQLStringList)    
        {    
            using (OleDbConnection conn = new OleDbConnection(connectionString))    
            {    
                conn.Open();    
                using (OleDbTransaction trans = conn.BeginTransaction())    
                {    
                    OleDbCommand cmd = new OleDbCommand();    
                    try  
                    {    
                        //循环    
                        foreach (DictionaryEntry myDE in SQLStringList)    
                        {    
                            string cmdText = myDE.Key.ToString();    
                            OleDbParameter[] cmdParms = (OleDbParameter[])myDE.Value;    
                            PrepareCommand(cmd, conn, trans, cmdText, cmdParms);    
                            int val = cmd.ExecuteNonQuery();    
                            cmd.Parameters.Clear();    
  
                            trans.Commit();    
                        }    
                    }    
                    catch  
                    {    
                        trans.Rollback();    
                        throw;    
                    }    
                }    
            }    
        }      
  
        /// <summary>    
        /// 执行一条计算查询结果语句，返回查询结果（object）。    
        /// </summary>    
        /// <param name="SQLString">计算查询结果语句</param>    
        /// <returns>查询结果（object）</returns>    
        public static object GetSingle(string SQLString, params OleDbParameter[] cmdParms)    
        {    
            using (OleDbConnection connection = new OleDbConnection(connectionString))    
            {    
                using (OleDbCommand cmd = new OleDbCommand())    
                {    
                    try  
                    {    
                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);    
                        object obj = cmd.ExecuteScalar();    
                        cmd.Parameters.Clear();    
                        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))    
                        {    
                            return null;    
                        }    
                        else  
                        {    
                            return obj;    
                        }    
                    }    
                    catch (System.Data.OleDb.OleDbException e)    
                    {    
                        throw new Exception(e.Message);    
                    }    
                }    
            }    
        }    /* 何问起 hovertree.com */
  
        /// <summary>    
        /// 执行查询语句，返回SqlDataReader (使用该方法切记要手工关闭SqlDataReader和连接)    
        /// </summary>    
        /// <param name="strSQL">查询语句</param>    
        /// <returns>SqlDataReader</returns>    
        public static OleDbDataReader ExecuteReader(string SQLString, params OleDbParameter[] cmdParms)    
        {    
            OleDbConnection connection = new OleDbConnection(connectionString);    
            OleDbCommand cmd = new OleDbCommand();    
            try  
            {    
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);    
                OleDbDataReader myReader = cmd.ExecuteReader();    
                cmd.Parameters.Clear();    
                return myReader;    
            }    
            catch (System.Data.OleDb.OleDbException e)    
            {    
                throw new Exception(e.Message);    
            }    
            //finally //不能在此关闭，否则，返回的对象将无法使用    
            //{    
            //  cmd.Dispose();    
            //  connection.Close();    
            //}      
        }    
  
        /// <summary>    
        /// 执行查询语句，返回DataSet    
        /// </summary>    
        /// <param name="SQLString">查询语句</param>    
        /// <returns>DataSet</returns>    
        public static DataSet Query(string SQLString, params OleDbParameter[] cmdParms)    
        {    
            using (OleDbConnection connection = new OleDbConnection(connectionString))    
            {    
                OleDbCommand cmd = new OleDbCommand();    
                PrepareCommand(cmd, connection, null, SQLString, cmdParms);    
                using (OleDbDataAdapter da = new OleDbDataAdapter(cmd))    
                {    
                    DataSet ds = new DataSet();    
                    try  
                    {    
                        da.Fill(ds, "ds");    
                        cmd.Parameters.Clear();    
                    }    
                    catch (System.Data.OleDb.OleDbException ex)    
                    {    
                        throw new Exception(ex.Message);    
                    }    
                    return ds;    
                }    
            }    
        }      
  
        private static void PrepareCommand(OleDbCommand cmd, OleDbConnection conn, OleDbTransaction trans, string cmdText, OleDbParameter[] cmdParms)    
        {    
            if (conn.State != ConnectionState.Open)    
                conn.Open();    
            cmd.Connection = conn;    
            cmd.CommandText = cmdText;    
            if (trans != null)    
                cmd.Transaction = trans;    
            cmd.CommandType = CommandType.Text;//cmdType;    
            if (cmdParms != null)    
            { 
                foreach (OleDbParameter parameter in cmdParms)    
                {    
                    if ((parameter.Direction == ParameterDirection.InputOutput || parameter.Direction == ParameterDirection.Input) &&    
                        (parameter.Value == null))    
                    {    
                        parameter.Value = DBNull.Value;    
                    }    
                    cmd.Parameters.Add(parameter);    
                }    
            }    
        }  
  
        #endregion  
  
        #region 获取根据指定字段排序并分页查询
  
  
        /* 何问起 hovertree.com */  
        /// <summary>    
        /// 分页查询数据记录总数获取    
        /// </summary>    
        /// <param name="_tbName">----要显示的表或多个表的连接</param>    
        /// <param name="_ID">----主表的主键</param>    
        /// <param name="_strCondition">----查询条件,不需where</param>            
        /// <param name="_Dist">----是否添加查询字段的 DISTINCT 默认0不添加/1添加</param>    
        /// <returns></returns>    
        public static string getPageListCounts(string _ID, string _tbName, string _strCondition, int _Dist)    
        {    
            //---存放取得查询结果总数的查询语句                        
            //---对含有DISTINCT的查询进行SQL构造    
            //---对含有DISTINCT的总数查询进行SQL构造    
            string strTmp = "", SqlSelect = "", SqlCounts = "";    
  
            if (_Dist == 0)    
            {    
                SqlSelect = "Select ";    
                SqlCounts = "COUNT(*)";    
            }    
            else  
            {    
                SqlSelect = "Select DISTINCT ";    
                SqlCounts = "COUNT(DISTINCT " + _ID + ")";    
            }    
            if (_strCondition == string.Empty)    
            {    
                strTmp = SqlSelect + " "+ SqlCounts + " FROM " + _tbName;    
            }    
            else  
            {    
                strTmp = SqlSelect + " "+ SqlCounts + " FROM " + " Where (1=1) " + _strCondition;    
            }    
            return strTmp;    
        }      
  
        /// <summary>    
        /// 智能返回SQL语句    
        /// </summary>    
        /// <param name="primaryKey">主键（不能为空）</param>    
        /// <param name="queryFields">提取字段（不能为空）</param>    
        /// <param name="tableName">表（理论上允许多表）</param>    
        /// <param name="condition">条件（可以空）</param>    
        /// <param name="OrderBy">排序，格式：字段名+""+ASC（可以空）</param>    
        /// <param name="pageSize">分页数（不能为空）</param>    
        /// <param name="pageIndex">当前页，起始为：1（不能为空）</param>    
        /// <returns></returns>      
        public static string getPageListSql(string primaryKey, string queryFields, string tableName, string condition, string orderBy, int pageSize, int pageIndex)    
        {    
            string strTmp = ""; //---strTmp用于返回的SQL语句    
            string SqlSelect = "", SqlPrimaryKeySelect = "", strOrderBy = "", strWhere = " where 1=1 ", strTop = "";    
            //0：分页数量    
            //1:提取字段    
            //2:表    
            //3:条件    
            //4:主键不存在的记录    
            //5:排序    
            SqlSelect = " select top {0} {1} from {2} {3} {4} {5}";    
            //0:主键    
            //1:TOP数量,为分页数*(排序号-1)    
            //2:表    
            //3:条件    
            //4:排序    
            SqlPrimaryKeySelect = " and {0} not in (select {1} {0} from {2} {3} {4}) ";      
            if (orderBy != "")    
                strOrderBy = " order by " + orderBy;    
            if (condition != "")    
                strWhere += " and " + condition;    
            int pageindexsize = (pageIndex - 1) * pageSize;    
            if (pageindexsize > 0)    
            {    
                strTop = " top " + pageindexsize.ToString();    
  
                SqlPrimaryKeySelect = String.Format(SqlPrimaryKeySelect, primaryKey, strTop, tableName, strWhere, strOrderBy);    
  
                strTmp = String.Format(SqlSelect, pageSize.ToString(), queryFields, tableName, strWhere, SqlPrimaryKeySelect, strOrderBy);    
  
            }    
            else  
            {    
                strTmp = String.Format(SqlSelect, pageSize.ToString(), queryFields, tableName, strWhere, "", strOrderBy);    
  
            }    
            return strTmp;    
        }      
  
        /// <summary>    
        /// 获取根据指定字段排序并分页查询。DataSet    
        /// </summary>    
        /// <param name="pageSize">每页要显示的记录的数目</param>    
        /// <param name="pageIndex">要显示的页的索引</param>    
        /// <param name="tableName">要查询的数据表</param>    
        /// <param name="queryFields">要查询的字段,如果是全部字段请填写：*</param>    
        /// <param name="primaryKey">主键字段，类似排序用到</param>    
        /// <param name="orderBy">是否为升序排列：0为升序，1为降序</param>    
        /// <param name="condition">查询的筛选条件</param>    
        /// <returns>返回排序并分页查询的DataSet</returns>    
        public static DataSet GetPagingList(string primaryKey, string queryFields, string tableName, string condition, string orderBy, int pageSize, int pageIndex)    
        {    
            string sql = getPageListSql(primaryKey, queryFields, tableName, condition, orderBy, pageSize, pageIndex);    
  
            return Query(sql);    
        }    
        public static string GetPagingListSQL(string primaryKey, string queryFields, string tableName, string condition, string orderBy, int pageSize, int pageIndex)    
        {    
            string sql = getPageListSql(primaryKey, queryFields, tableName, condition, orderBy, pageSize, pageIndex);    
  
            return sql;    
        }    
        public static int GetRecordCount(string _ID, string _tbName, string _strCondition, int _Dist)    
        {    
            string sql = getPageListCounts( _ID,  _tbName,  _strCondition,  _Dist);    
  
            object obj = AccessDBHelper.GetSingle(sql);    
            if (obj == null)    
            {    
                return 1;    
            }    
            else  
            {    
                return int.Parse(obj.ToString());    
            }    
        }  
        #endregion      


        #region old code 
        /*
                public static void excuteSql(string sqlstr)
        {
            try
            {
                openConnection();
                comm.CommandType = CommandType.Text;
                comm.CommandText = sqlstr;
                comm.ExecuteNonQuery();
            }
            catch (Exception e)
            {
                throw new Exception(e.Message);
            }
            finally
            { closeConnection(); }
        }
        /// <summary>
        /// 返回指定sql语句的OleDbDataReader对象，使用时请注意关闭这个对象。
        /// </summary>
        /// <param name="sqlstr"></param>
        /// <returns></returns>
        public static OleDbDataReader dataReader(string sqlstr)
        {
            OleDbDataReader dr = null;
            try
            {
                openConnection();
                comm.CommandText = sqlstr;
                comm.CommandType = CommandType.Text;

                dr = comm.ExecuteReader(CommandBehavior.CloseConnection);
            }
            catch
            {
                try
                {
                    dr.Close();
                    closeConnection();
                }
                catch { }
            }
            return dr;
        }
        /// <summary>
        /// 返回指定sql语句的OleDbDataReader对象,使用时请注意关闭
        /// </summary>
        /// <param name="sqlstr"></param>
        /// <param name="dr"></param>
        public static void dataReader(string sqlstr, ref OleDbDataReader dr)
        {
            try
            {
                openConnection();
                comm.CommandText = sqlstr;
                comm.CommandType = CommandType.Text;
                dr = comm.ExecuteReader(CommandBehavior.CloseConnection);
            }
            catch
            {
                try
                {
                    if (dr != null && !dr.IsClosed)
                        dr.Close();
                }
                catch
                {
                }
                finally
                {
                    closeConnection();
                }
            }
        }
        /// <summary>
        /// 返回指定sql语句的dataset
        /// </summary>
        /// <param name="sqlstr"></param>
        /// <returns></returns>
        public static DataSet dataSet(string sqlstr)
        {
            DataSet ds = new DataSet();
            OleDbDataAdapter da = new OleDbDataAdapter();
            try
            {
                openConnection();
                comm.CommandType = CommandType.Text;
                comm.CommandText = sqlstr;
                da.SelectCommand = comm;
                da.Fill(ds);

            }
            catch (Exception e)
            {
                throw new Exception(e.Message);
            }
            finally
            {
                closeConnection();
            }
            return ds;
        }
        /// <summary>
        /// 返回指定sql语句的dataset
        /// </summary>
        /// <param name="sqlstr"></param>
        /// <param name="ds"></param>
        public static void dataSet(string sqlstr, ref DataSet ds)
        {
            OleDbDataAdapter da = new OleDbDataAdapter();
            try
            {
                openConnection();
                comm.CommandType = CommandType.Text;
                comm.CommandText = sqlstr;
                da.SelectCommand = comm;
                da.Fill(ds);
            }
            catch (Exception e)
            {
                throw new Exception(e.Message);
            }
            finally
            {
                closeConnection();
            }
        }
        /// <summary>
        /// 返回指定sql语句的datatable
        /// </summary>
        /// <param name="sqlstr"></param>
        /// <returns></returns>
        public static DataTable dataTable(string sqlstr)
        {
            DataTable dt = new DataTable();
            OleDbDataAdapter da = new OleDbDataAdapter();
            try
            {
                openConnection();
                comm.CommandType = CommandType.Text;
                comm.CommandText = sqlstr;
                da.SelectCommand = comm;
                da.Fill(dt);
            }
            catch (Exception e)
            {
                throw new Exception(e.Message);
            }
            finally
            {
                closeConnection();
            }
            return dt;
        }
        /// <summary>
        /// 返回指定sql语句的datatable
        /// </summary>
        /// <param name="sqlstr"></param>
        /// <param name="dt"></param>
        public static void dataTable(string sqlstr, ref DataTable dt)
        {
            OleDbDataAdapter da = new OleDbDataAdapter();
            try
            {
                openConnection();
                comm.CommandType = CommandType.Text;
                comm.CommandText = sqlstr;
                da.SelectCommand = comm;
                da.Fill(dt);
            }
            catch (Exception e)
            {
                throw new Exception(e.Message);
            }
            finally
            {
                closeConnection();
            }
        }
        /// <summary>
        /// 返回指定sql语句的dataview
        /// </summary>
        /// <param name="sqlstr"></param>
        /// <returns></returns>
        public static DataView dataView(string sqlstr)
        {
            OleDbDataAdapter da = new OleDbDataAdapter();
            DataView dv = new DataView();
            DataSet ds = new DataSet();
            try
            {
                openConnection();
                comm.CommandType = CommandType.Text;
                comm.CommandText = sqlstr;
                da.SelectCommand = comm;
                da.Fill(ds);
                dv = ds.Tables[0].DefaultView;
            }
            catch (Exception e)
            {
                throw new Exception(e.Message);
            }
            finally
            {
                closeConnection();
            }
            return dv;
        }

        /// <summary>
        /// 取首行首列值
        /// </summary>
        /// <param name="sqlstr"></param>
        /// <returns></returns>
        public static object ExecuteScalar(string sqlstr)
        {
            object ret = null;
            try
            {
                openConnection();
                comm.CommandType = CommandType.Text;
                comm.CommandText = sqlstr;
                ret=comm.ExecuteScalar();               
            }
            catch (Exception e)
            {
                throw new Exception(e.Message);
            }
            finally
            { closeConnection(); }

            return ret;
        }  
        */
        #endregion
    }    
}
